The operation of most agricultural vehicles requires substantial operational involvement and control by the operator. For example, in a cotton harvester the operator is required to control the direction and speed of the vehicle while also controlling the height of the harvesting drum, the amount of harvested crop stored on the vehicle and a variety of other operation conditions. Accordingly, to reduce the effort required by the operator, it is useful to automate as many tasks performed by the operator as possible.
Conventional cotton harvesters include two or more harvesting implements commonly supported for vertical movement on a fore-and-aft wheeled frame of the harvester. Each harvesting implement includes a harvesting assembly defining a plant passage and a harvesting mechanism arranged within the housing. As the cotton harvester is driven across the cotton field, a row of cotton plants passes through the passage, and the harvesting mechanism removes the cotton therefrom. Cotton grows along the entire height of the cotton plant. At the lower end, the cotton grows barely off the ground and sometimes on the ground. The harvesting implements, therefore, follow as close to the ground as possible so as to pick or harvesting is as much of the cotton from the plants.
The ground over which the harvester is driven is usually uneven. Accordingly, if the harvesting implement is set for a lowermost point of depression on the ground, stalk lifters extending from a forward end of the harvesting implement will tend to “dig into” high points of ground contour. As the harvester is driven across the field, the wheels on the harvester frame ride between adjacent rows of cotton plants. In softer muddy conditions, the wheels of the harvester furthermore deform the field into slight recesses and valleys or raised ridges. As will be appreciated, proper positioning of the harvesting implement relative to the ground contour is further complicated in such undulating field conditions.
To optimize efficiency during the harvesting operation, cotton harvesters are known to include a harvesting implement height control system for automatically controlling the height of the harvesting implement relative to the ground contour. The elevation of the harvesting implement is primarily controlled by a lift mechanism actuated in accordance with ground contours. Variations of the ground contour are sensed by a ground engaging element, such as a shoe, mounted on the harvesting implement in a manner to press on the ground and be positionally displaced in response to variations of the ground contour profile.
During the harvesting process for cotton, it is generally necessary to maintain the harvesting implements in close proximity to the ground (0.5-3.0 inches) to ensure optimal harvesting. Upon reaching the end of the harvested row, the operator typically disengages automatic height control, with the operator's attention focused on reversing the directional headings of the harvester and effecting realignment of the harvesting implement with the next row to continue harvesting the cotton crop, prior to re-engaging the automatic implement height control system. While the harvester is in this transitional stage, it is not necessary to maintain the harvesting implements in such close proximity to the ground, as ongoing crop harvesting is not occurring. Further, a change in terrain may cause damage to the harvesting implements.
Accordingly, it would be desirable to provide an automated implement height adjustment arrangement and method that provides protection of the harvesting implement while ongoing crop harvesting is not occurring.